RabbitMQ 入门教程

概述

RabbitMQ 是一个开源的消息代理和队列服务器，实现了 AMQP 0-9-1 标准。它可以在完全不同的应用程序之间作为消息的中转站。

安装 RabbitMQ

1. 安装 RabbitMQ Server

Ubuntu:

sudo apt update

sudo apt install rabbitmq-server

macOS (通过 Homebrew):

brew install rabbitmq

2. 启动服务

sudo service rabbitmq-server start

3. 开启管理插件

sudo rabbitmq-plugins enable rabbitmq_management

4. 访问管理界面

• 打开浏览器访问: http://localhost:15672/

• 默认用户名/密码: guest/guest

创建第一个应用

我们将创建两个简单的程序：

1. Producer - 发送消息到 RabbitMQ。

2. Consumer - 接收并处理消息。

1. 设置环境

确保安装了 Python 和 pika 库。

pip install pika

2. Producer 示例

import pika

connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))

channel = connection.channel()

channel.queue_declare(queue='hello')

channel.basic_publish(exchange='',

routing_key='hello',

body='Hello World!')

print(" [x] Sent 'Hello World!'")

connection.close()

3. Consumer 示例

import pika

def callback(ch, method, properties, body):

print(" [x] Received %r" % body)

connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))

channel = connection.channel()

channel.queue_declare(queue='hello')

channel.basic_consume(queue='hello',

on_message_callback=callback,

auto_ack=True)

print(' [*] Waiting for messages. To exit press CTRL+C')

channel.start_consuming()

高级功能

1. 工作队列

工作队列用于负载均衡，将任务分散到多个工作者上。

Producer:

import pika

connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))

channel = connection.channel()

channel.queue_declare(queue='task_queue', durable=True)

message = "A new task"

channel.basic_publish(exchange='',

routing_key='task_queue',

body=message,

properties=pika.BasicProperties(

delivery_mode = 2, # make message persistent

))

print(" [x] Sent %r" % message)

connection.close()

Consumer:

import pika

import time

def callback(ch, method, properties, body):

print(" [x] Received %r" % body)

time.sleep(body.count(b'.'))

print(" [x] Done")

ch.basic_ack(delivery_tag=method.delivery_tag)

connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))

channel = connection.channel()

channel.queue_declare(queue='task_queue', durable=True)

print(' [*] Waiting for messages. To exit press CTRL+C')

channel.basic_qos(prefetch_count=1)

channel.basic_consume(queue='task_queue',

on_message_callback=callback)

channel.start_consuming()

2. 发布/订阅模式

发布/订阅模式允许多个消费者订阅同一个交换器。

Publisher:

import pika

connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))

channel = connection.channel()

channel.exchange_declare(exchange='logs', exchange_type='fanout')

message = "Info: Hello World!"

channel.basic_publish(exchange='logs',

routing_key='',

body=message)

print(" [x] Sent %r" % message)

connection.close()

Consumers:

```python

import pika

def callback(ch, method, properties, body):

print(" [x] Received %r" % body)

connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))

channel = connection.channel()

channel.exchange_declare(exchange='logs', exchange_type='fanout')

result = channel.queue_declare(queue='', exclusive=True)

queue_name = result.method.queue

channel.queue_bind(exchange='logs', queue=queue_name)

print(' [*] Waiting for logs. To exit press CTRL+C')

channel.basic_consume(queue=queue_name,

on_message_callback=callback,

auto_ack=True)

channel.start_consuming()